KR970001628B1 - Projection system and image projection method - Google Patents

Abstract

None.

Description

Image Projection and Projection Display

1 is an optical system layout diagram illustrating a first embodiment of an image projection method and a projection display device according to the present invention.

2 is a schematic front view showing an example of the rear projection type television receiver according to the present invention incorporating a projection cathode ray tube.

3 is a schematic diagram showing a cross-sectional structure of the rear projection type television receiver shown in FIG.

Figure 4 is a side view showing the main portion of a second embodiment of a color image projection apparatus using a projection type cathode ray tube according to the present invention.

FIG. 5 is a schematic diagram showing a side structure of a rear projection television similar to FIG. 3 having the configuration of FIG.

6A and 6B are explanatory diagrams of the size of an original image formed on a fluorescent surface of a projection cathode ray tube and an electron beam spot shape at the center of the screen;

FIG. 7 is a schematic perspective view showing an example of a horizontal magnification optical system EXT, which is an image extension optical system shown in FIG.

8 is a schematic diagram of an all-optical system illustrating a third embodiment of the present invention.

9 is a schematic diagram of an entire optical system for explaining a fourth embodiment of the present invention;

10A and 10B are explanatory diagrams of the size of a liquid crystal panel and the shape of a pixel cell used to form an original image.

Fig. 11 is a partial sectional view illustrating the structure of a projection type cathode ray tube used in the present invention.

* Explanation of symbols for main parts of the drawings

(rPRT): Red image projected cathode ray tube (gPRT): Green image projected cathode ray tube

(bPRT): Blue image projection cathode ray tube (PNL): Panel part (fluorescent surface)

(CMP): Image compression means (LNS): Projection lens

(EXT): Horizontal Magnification Optics

(CPL): Combiner (Lh): Horizontal length of the image

(Lv): length in the vertical direction of the image (D): diagonal diameter of the image

(BM): shape of the battery beam spot on the phosphor screen

(dh): horizontal diameter of the electron beam (dv): vertical diameter of the electron beam

(x): horizontal direction (y): vertical direction

(z): Optical axis direction (M): Mirror

(DM): Screening Mirror (DP): Screening Prism

(LCP): Liquid Crystal Panel (LM): Lamp

(CL): Capacitor Lens (C): Pixel Cell

(ah): Horizontal length of pixel cell (av): Vertical length of pixel cell (1): Projection screen (2): Mirror

The present invention relates to an image projection method and a projection display device. In particular, the present invention relates to an image projection method and a projection display device having improved brightness and contrast of an enlarged image projected on a projection screen.

A conventional projection display device has a structure in which a fluorescent screen of a projection cathode ray tube or an original image formed on a liquid crystal panel is projected onto a projection screen by a projection optical system whose horizontal and vertical directions are the same magnification.

In a projection display device using a projection cathode ray tube, an original image is formed by firing collision of a large current value with an electron beam on the fluorescent surface thereof, and the binary image is projected onto a projection screen in an enlarged projection optical system.

In order to increase the luminance of the original image formed on the fluorescent surface and to increase the luminance and contrast of the image projected on the screen, for example, an electron beam for forming the original image as in the invention disclosed in Japanese Patent Laid-Open No. 54-561. It is necessary to reduce the spot diameter and increase the current density of the fluorescent surface. However, the fluorescent surface has a high temperature due to the firing collision of the electron beam of this large current. As a result, the luminous efficiency of the phosphor decreases and the enlarged image projected on the projection screen. Brightness and contrast decrease. In addition, when the fluorescent surface of the projection cathode ray tube approaches the magnified projection optical system, light is reflected between them, which also causes a decrease in the brightness and contrast of the image on the screen.

In order to solve such a problem, there is an invention disclosed in Japanese Patent Application Laid-Open No. 48-90628 in which the former has a cooling structure on the fluorescent screen and suppresses the temperature rise of the fluorescent screen.

In order to solve the latter problem, an invention disclosed in Japanese Patent Application Laid-Open No. 58-194234 in which an antireflection medium is interposed between a fluorescent surface and an optical system is known.

Further, examples of the general configuration related to this type of projection display include the television journal "Projection Large Screen Display" Nos. 164 to (February 1991).

When the projection type cathode ray tube shown in the prior art is used to handle an image having a different size (hereinafter referred to as an aspect ratio), that is, an image having a different length and width from the image, in particular, an aspect ratio such as high vision is extremely extreme. In the case of projecting a large image, the original image formed on the section steel surface of the projection type cathode ray tube is long in width.

Since the original image formed on the fluorescent surface is limited to the size of the long wall (generally, the horizontal direction: the horizontal direction), the area of the image falling into the projectable diameter (effective diameter) of the projection optical system becomes relatively small. As a result, there is a problem that the total luminous flux on the screen decreases, the luminance of the projection image on the projection screen is lowered, and the contrast is lowered. This is true even when the means for forming the original image is not limited to the projection type cathode ray tube, for example, when image forming means such as a liquid crystal panel is used.

An object of the present invention is to make the area of the original image that enters the effective diameter of the projection optical system as large as possible while keeping the projectable diameter of the projection optical system constant, and increase the total luminous flux on the projection screen to project onto the projection screen. The present invention provides an image projection method and a projection display device with improved screen luminance and improved contrast.

In order to achieve the above object, the present invention provides a projection type display device using a cathode ray tube or a liquid crystal panel, wherein an image long in the horizontal direction (horizontal direction) or in the vertical direction (vertical direction) (a ratio of width and length in a standard television system). 4: 3, and 16: 9 in the high-vision system, are compressed so that their vertical and horizontal sizes are the same or almost the same, and reflected on the original image forming means such as the fluorescent screen or liquid crystal panel of the cathode ray tube. The projection optical system extends to the original aspect ratio and projects it on the projection screen, which is embodied as a projection display device.

In this case, preferably, in the display device using the projection type cathode ray tube, the electron beam spot shape on the fluorescent surface is long elliptical in the direction in which the compression ratio of the original image is small (usually in the vertical direction), and the liquid crystal display element is used. In a projection display device using a panel type display element (hereinafter referred to as a liquid crystal panel), the shape of the pixel of the liquid crystal panel is long rectangular in the vertical direction (the direction in which the compression ratio is small). The size of the original image formed on the fluorescent screen of the cathode ray tube or the liquid crystal panel becomes a rectangle whose aspect ratio is almost one.

In addition. Preferably, the elliptical electron beam spot of the projection type cathode ray tube forming the original image or the ratio of the length in the horizontal direction and the vertical direction of the rectangular cell of the liquid crystal panel is set as the ratio of the length in the vertical direction and the horizontal direction of the original image. do.

That is, the present invention provides an image projection method having an original image forming means, a projection optical system, and a projection means, and projecting an original image formed on the original image forming means to the projection unit by the projection optical system. The original image forming means includes an original image obtained by compressing the original image so that the absolute value of the difference between the length and width of the image is smaller than that of the original image, so as to be different from the ratio of the length and width of the original image. And forming, and projecting the formed original image onto the projection means by the projection optical system, and extending by the image extension means to the ratio of the length of the original image to the length of the original image. do. In terms of apparatus, a projection type cathode ray tube having a fluorescent surface and a projection optical system and projection screen for enlarging and projecting an original image formed on the fluorescent surface of the projection type cathode ray tube can be compared with an original image. Image compression means for compressing the original image so as to be different from the ratio between the length and the length of the original image so that the absolute value of the difference between the length and the length of the image is small, and forming the original image on the fluorescent surface of the projection cathode ray tube. And an image extension optical system for projecting the original image formed on the fluorescent screen to the projection screen as a ratio between the length and the length of the original image. And the image extension optical system is an optical lens provided on the projection screen side of the projection optical system, or a convex mirror provided between the projection optical system and the projection screen.

The electron beam spot shape on the fluorescent surface is compressed at a compression ratio corresponding to the compression ratio in the compression direction of the original image.

In addition, the present invention provides a projection type display device having a light source lamp, a liquid crystal panel having a plurality of pixel cells in a lattice shape, and a projection optical system and a projection screen for enlarging and projecting an original image formed on the liquid crystal panel. And an image extension optical system projecting on the projection screen as a ratio of the length of the image to the length of the image as compared with the above-mentioned image, wherein each pixel cell constituting the liquid crystal panel has a compression ratio in the compression direction of the original image. It is characterized by the shape compressed at the corresponding compression rate.

By reducing the aspect ratio (ratio of the length of the image to the length of the image) of the image formed by the original image forming means, the area of the rectangular image inscribed in the effective diameter velocity of the circular projection optical system is maximized. Therefore, it has the maximum total light velocity projected on the projection screen, and the screen luminance on the projection screen is improved, and the contrast is also high.

Further, the electron beam width on the fluorescent surface of the projection cathode ray tube is compressed in the same direction as the compression direction of the size of the original image formed on the fluorescent surface (for example, a long oval) or a pixel of the liquid crystal panel. The shape in which the cell is compressed in the same direction as the compression direction of the size of the original image (e.g., a vertical rectangle), and the horizontal and vertical images of the enlarged image that are stretched to the original aspect ratio in the image extension optical system and projected onto the image screen. The balance of the resolution of the direction can be kept well.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In general, a projection image display apparatus uses a projection cathode ray tube, a projection liquid crystal panel, or the like as an image forming means, and arranges the image forming means at a position separated from the projection screen by a distance, and forms a circle formed on the image forming means. The image is projected on the projection screen in the magnification optical system.

FIG. 11 is a partial cross-sectional view illustrating the structure of a projection cathode ray tube used in one embodiment of the present invention. In particular, an example of a North American convergence type projection cathode ray tube using an electron lens and an electrostatic lens is shown.

In the same drawing, an electron gun GUN for radiating, controlling, accelerating, and converging an electron beam BEM is housed in the neck portion of the glass bulb BLB, and the funnel portion of the glass bulb BLB is housed. PNL) That is, the front surface side is formed with a monochromatic fluorescent surface (SRN) deposited on its inner surface to form a cathode ray tube (PRT).

Further, around the funnel portion FNL of the glass bulb BLB, a deflection yoke DY for deflecting the electron beam BEM emitted from the electron gun GUN in the horizontal and vertical directions is mounted, and the fluorescent surface SRN is provided. ) Light up the whole surface. Also adjacent to the neck of the deflection yoke DY, a focusing yoke CY for correcting color shift (non-focusing) of an image reproduced in the projection type cathode ray tube PRT of each color and an electron beam A central focusing magnet (BCM) for adjusting the pre-output position of the BEM and a focusing magnet (MFM) for forming an electron lens (MFL) for conducting the procedure of the electron beam (BEM) are mounted.

Further, on the outer circumference of the neck portion NCK, in which the electron gun GUN is housed, for correcting the central axis of the electron lens MFL formed by the focusing magnet MMF and the passage axis of the electron beam BEM. A non-alignment magnet (BAM) is mounted.

The aspect ratio of the original image formed on the fluorescent surface of the projection cathode ray tube can be arbitrarily set by a deflection waveform applied to the deflection yoke DY or by an image signal processing circuit.

In addition, the output shape on the fluorescent surface of the electron beam can be controlled by controlling the electrode configuration of the electron gun, or an applied electric field or magnetic field.

Currently, projection type cathode ray tubes (PRTs) are mainly used in projection type image display apparatuses, but recently, projection image display apparatuses using liquid crystal display panels as the original image forming means instead of such cathode ray tubes have been put into practical use.

The aspect ratio of the original image formed on the liquid crystal panel can be structurally set as the aspect ratio of the liquid crystal cell of the liquid crystal panel itself.

Hereinafter, each embodiment in which the present invention uses the projection type cathode ray tube and the liquid crystal panel as the original image forming means will be described in detail.

1 is an optical system arrangement diagram illustrating a first embodiment of an image projection method and a projection display device according to the present invention.

In the figure, (rPRT) is a red image projection cathode ray tube, (gPRT) is a green image projection cathode ray tube, (bPRT) is a blue image projection cathode ray tube, and a green image projection cathode ray tube (gPRT) is the central axis. On the upper side, it is arrange | positioned at the projection screen 1 in the position which separated | separated predetermined distance from the faceplate panel part PNL.

Further, projection optical systems, that is, projection lens systems (LNS), are arranged on the front side of the faceplate panel portions PNL of the projection cathode cathode ray tubes rPRT, gPRT, and bPRT, respectively, on the same line as their central axes. And monochromatic images (r: red, g: green, b: blue) formed on the faceplate panel (PNL) of the projection cathode ray tubes (rPRT), (gPRT) and (bPRT) to each projection lens system (LNS). By condensing and magnifying each of them, and projected on the projection screen, three colors can be combined with each other to obtain a superimposed color image.

In the figure, the image compression means (CMP) is a means for compressing the original image on the faceplate panel portion (fluorescent surface) so that its aspect ratio (a ratio of vertical and horizontal sizes) is almost 1, and is an image extension optical system. The systems rEXT, gEXT, and bEXT constitute image expansion means for enlarging the original image formed on the face plate panel portion PNL in the horizontal direction to make the original image size.

The projection display device having such a configuration can easily realize a large screen, high brightness and high contrast reproduction image as compared with a video device such as a direct-view television.

As an example of a projection display device, the above-mentioned public-use projection televisions are prevalent, but since they are large screens, compactness (thinning) of television sets is required.

FIG. 2 is a schematic front view showing an example of a rear projection type television receiver (hereinafter simply referred to as a rear projection type television) having a built-in projection cathode sarcophagus, and FIG. 3 is a schematic diagram showing a cross-sectional structure of FIG.

3, the projection lens LNS is coupled to the projection cathode ray tubes PRT (rPRT, gPRT and bPRT) via a coupler CPL, and is disposed below the set of the television. The focused image is condensed through the projection lens LNS and (EXT (rEXT, gEXT, bEXT)), and the enlarged reproduced image is reflected by a mirror 2 arranged at an appropriate angle on the television set. You can get a projected image on the projection screen.

4 is a side view showing the main portion of a second embodiment of the color image projection apparatus using the projection type cathode ray tube according to the present invention.

In the figure, the same reference numerals as those in FIG. 1 correspond to the same parts, and (EXTM) is another means of an optical system (image extension optical system) for stretching an image, which is a feature of the present invention, in the horizontal direction.

In this embodiment, instead of the optical system EXT of the above embodiment, a mirror EXTM having a convex mirror surface in the horizontal direction is used.

FIG. 5 is a schematic diagram showing the side structure of a rear projection television similar to FIG. 3 having the configuration of FIG.

In FIG. 5, there are three (EXT), (rEXT, gEXT, and bEXT) shown in FIG. 3, but since FIG. 3 is a cross-sectional structure of FIG. 2 viewed from the side, (EXT) is 1 Instead of the mirror), a mirror (EXTM) having a convex mirror surface in one horizontal direction is provided in place of the mirror of FIG. Also with this structure, an optical system (that is, an image extension optical system) for enlarging the image in the horizontal direction can be configured.

The television of the projection type cathode ray tube built-in type using the rear projection as described above is advantageous in compacting since the projection distance can be increased and the depth of the television set can be made thin.

6 (a) and 6 (b) are explanatory views of the size of the original image formed on the fluorescent surface (faceplate panel) of the projection type cathode ray tube and the electron beam spot shape at the center of the screen, and FIG. The size of the image formed on the fluorescent surface of the projection cathode ray tube by the conventional method and the electron beam spot shape at the center of the screen, FIG. 6 (b) shows the size and the screen of the image formed on the fluorescent surface of the projection cathode ray tube by the method of the present invention. The electron beam spot shape in the center part is displayed.

In FIGS. 6A and 6B, assuming that the projection lenses LMS are the same, the diagonal diameters D of the images that can be projected by the projection lenses are both the same. The ratio of the width and height of the image is different from the standard television system and the high-vision system, and the ratio of the width Lh and the height Lv of the image in the case of the standard television is 4: 3, and the width Lh and the height of the image in the high-vision system. The ratio of Lv is 4: 3, and the ratio of the width Lh 'and the height Lv' of the image in the high-vision system is 16: 9.

In a conventional projection optical system, the original image shown in Fig. 6A is projected onto the projection screen at the same magnification in the horizontal direction (width Lh direction) and vertical direction (height Lv direction). On the other hand, in the projection method according to the present invention, as shown in Fig. 6 (b), the ratio between the height Lh 'and the width Lv' of the image is almost 1, and in the conventional projection optical system, the image compressed in the horizontal direction is On the fluorescent surface. In order to project this onto the projection screen, a horizontally compressed image is illuminated.

In the above embodiment of the present invention, the original image formed on the fluorescent surface of the projection type cathode ray tube is extended by (EXT) or (EXTM) so that the horizontal size thereof is larger than the vertical size, so that the original width, Project to a height.

In addition, as shown in Fig. 6 (a), in the prior art, the electron beam spot shape on the fluorescent surface is circular, but in the embodiment of the present invention, as shown in Fig. 6 (b), The elliptical shape is vertically long depending on the compression ratio of the image. For example, in the case where a high-vision image is formed on the fluorescent surface such that the height Lh 'and the width Lv' of the image are the same, the cathode ray spot on the phosphor screen is formed by the ratio of the vertical length to the horizontal length (dv / It is preferable to make dh) into the elliptical shape of 16: 9.

By the way, when the diameter in the diagonal direction is D and the ratio of the height and width of the image is a, the area S of the image display portion is given as follows.

S (a) = Lh × Lv = a / (1 + a ² ) × D ² .............................. .(One)

For example, if the diagonal diameter D is the same for a square image of a = 1 and a high vision image of a = 9/10, the area is compared.

S (1) / S (9/16) = 1.17 ... .........(2)

It becomes In other words, in the high-vision system, as shown in FIG. 6 (b), when the image is compressed in the horizontal direction, it can be seen that the amount of light that can be projected by the same projection lens diameter can be increased by about 17%. . Even if the horizontal enlarged optical system, that is, the image extension optical system EXT (FIG. 1) described below, the amount of light lost is only about 4%, the amount of light can be increased by 13% or more. In addition, when (EXTM) (FIG. 4) is used, the amount of light decreases further.

In addition, in the case of FIG. 6 (b), the length of the horizontal deflection can be made smaller than in the case of FIG. 6 (a), and the deflection power required for the horizontal deflection can be greatly reduced. In general, since the power required for horizontal deflection is much larger than the power required for vertical deflection, the secondary effect of reducing power consumption required for deflection in the scheme according to the present invention shown in FIG. have.

FIG. 7 is a schematic perspective view showing an example of a horizontal magnification optical system EXT, which is an image extension optical system shown in FIG.

In the same figure, x is a horizontal scanning direction of a projection type cathode ray tube, y is a vertical scanning direction, and z is an optical axis. This magnification optical system is formed of glass or plastic, and the thickness in the z direction is constant, almost independent of the y direction, and is set to increase as the absolute value of x increases. That is, it is a concave lens only in the horizontal direction (x direction). By this magnification optical system, the original image formed by being horizontally compressed on the fluorescent surface of each PRT (rPRT, gPRT, bPRT) is stretched in the horizontal direction, and the horizontal and vertical directions on the screen are the same aspect ratio as the original image. You can get an enlarged image with.

In addition. The shape of the electron beam spot on the fluorescent surface is a long ellipse in the longitudinal direction, but when it is projected onto the screen by the horizontal magnification optical system (EXT), it is circular and can display an image in which the resolution in the vertical and horizontal directions is balanced.

In the back projection display having a mirror as shown in FIG. 3, the same effect can be obtained by using an enlarged optical mirror having a mirror surface convex in the horizontal direction as shown in FIGS. The same effect can be obtained by combining the magnification optical lens of FIG. 7 and the magnification optical mirror of FIG.

The above is the case where this invention is applied to the cathode ray projection type display. Next, the example applied to liquid crystal projection type display is demonstrated.

In the liquid crystal projection type display, in simple terms, the film of the slide projector is replaced with one liquid crystal panel. Projection type display devices using three liquid crystal panels corresponding to red, green, and blue in terms of brightness and resolution are mainstream.

8 is a schematic diagram of a whole optical system for explaining a third embodiment of the present invention, and FIG. 9 is a schematic diagram of a whole optical system for explaining a fourth embodiment of the present invention.

Each of these embodiments constitutes a liquid crystal projection type display device, and the basic configuration is the same as those of FIGS. 8 and 9, and the optical system is composed of a white light source, three color resolution system, three color liquid crystal panel, three color composite system, a projection lens, and the like. Image height optical system-projection screen, (LM) lamp, (RF) reflector, (DM) dichroic mirror, (M) reflector, (CL) condenser lens, (LCP) liquid crystal panel, (DP) Silver synthetic prism, (LNS) is a projection lens, (EXT) is an extended optical lens, (SR) is a screen, (CMP) is an image compression means for forming an original image having an aspect ratio of almost 1 on a liquid crystal panel.

In FIG. 8, the white light from the light source LM is separated into three primary colors of R (red), G (green), and B (blue) by means of the color discriminating mirror DM. The image compression means CMP forms an original image of each color having an aspect ratio of approximately 1 on the liquid crystal panel LCP (rLCP, gLCP, bLCP), and separates the separated white light into each liquid crystal panel LCP (rLCP). After injecting into the gLCP and bLCP, modulating and synthesizing three colors by the synthesizing prism DP, the synthesized image is projected to the screen SC as the original image size by the projection lens LNS and the image extension optical system EXT. Projected onto).

In FIG. 8, (EXTM) shown in FIG. 4 may be used instead of (EXT).

In FIG. 9, color-dividing mirror (DM) is used instead of the synthetic prism in FIG. 8, and similarly, (EXTM) may be used instead of (EXT) as the image extension optical system.

10 (a) and 10 (b) are explanatory views of the size and shape of a pixel cell of a liquid crystal panel used to form an original image, and FIG. 10 (a) shows a conventional liquid crystal panel and its pixel cells; Fig. 10B shows a liquid crystal panel and its pixel cells in the embodiment of the present invention.

In Fig. 10 (a), the ratio between the width (horizontal direction) Lh and the width (vertical direction) Lv of the size of the original image formed on the liquid crystal panel is 16: 9 in the 4: 3 high version system in the standard television system. This image is projected on the projection screen at the same magnification in the horizontal and vertical directions by the projection optical system.

On the other hand, in the embodiment of the present invention shown in Fig. 10B, the ratio between the width Lh 'and the height Lv' of the size of the original image is almost one.

In addition, in the case of 10 degrees (a), the pixel cells C have a square shape, but in the case of FIG. 10 (b), the shape of the pixel cells C 'is shown as a compression ratio of the size of the original image. It is preferable to set it as the vertically long rectangle which has the shape which follows. For example, when the width Lh 'and the height Lv' of the image are the same in the high-vision method, the ratio (av / ah) between the vertical length av of the pixel cell and the horizontal length ah is set to a rectangle of 16: 9. It is preferable.

The horizontally compressed original image is stretched horizontally in the above-described image expansion optical system EXT or EXTM, so that the horizontal and vertical directions on the projection screen SC are the same as the original image. Obtain an enlarged image with a ratio. In addition, the image of a pixel cell which has become a vertically long rectangle becomes square when projected onto the projection screen SC by the projection screen SC by the horizontal magnification system EXT or EXTM. Images with a balanced resolution can be displayed.

Although the embodiment has been described as a projection display device of a color image, the present invention is not limited to this, and the present invention can also be applied to a monochromatic projection display device using one projection cathode ray tube or one liquid crystal panel.

As described above, according to the present invention, in the projection display device using the projection cathode ray tube or the projection display device using the liquid crystal panel, the total luminous flux can be maximized by enlarging the area of the image that can be projected by the magnification projection lens system. Therefore, the brightness of the image on the projection screen can be improved, and the contrast can also be increased.

In addition, the use of the projection type cathode ray tube can reduce the horizontal deflection of the electron beam, thereby reducing the power consumption required for deflection.

Claims (11)

In an image projection method having an original image forming means, a projection optical system, and a projection means, and projecting an original image formed on the original image forming means to the projection unit by the projection optical port, compared with an original image Forming an original image on the original image forming means by compressing the original image so that the absolute value of the difference between the vertical and horizontal lengths of the image becomes small so as to be different from the ratio of the vertical and horizontal lengths of the original image; And when the formed original image is projected by the projection optical system to the projection means, extending by a ratio of the length and the length of the original image by the image extension means. A projection type display device having a projection type cathode ray tube having a fluorescent surface and a projection optical system and projection screen for enlarging and projecting an original image formed on the fluorescent surface of the projection type cathode ray tube, the length of the image being vertical and horizontal in comparison with the original image Image compression means for compressing the original image so that the absolute value of the difference is small so as to be different from the ratio of the vertical to the horizontal of the original image, and forming the original image on the fluorescent surface of the projection cathode ray tube, and the original image formed on the fluorescent surface And an image height optical system for projecting the projection image to the projection screen as a ratio between the length and the length of the original image. The projection display device according to claim 2, wherein the image extension optical system is an optical lens provided on the projection screen side of the projection optical system. The projection display device according to claim 2, wherein the image extension optical system is a convex mirror provided between the projection optical system and the projection screen. The projection display device according to claim 2, 3 or 4, wherein the electron beam spot shape on the fluorescent surface is compressed by a compression ratio corresponding to the compression ratio in the compression direction of the original image. Projection type cathode ray tube for forming an original image in which the original image is compressed so as to be different from the ratio of the length to the length of the original image so that the absolute value of the difference between the length and the width of the image is smaller than the original image. A projection cathode ray tube for a projection display device, characterized in that the electron beam spot on the fluorescent surface of the film is compressed in the same direction by a compression ratio corresponding to a compression ratio corresponding to the compression ratio of the compression direction of the original image. A projection type display device having an optical lamp, a liquid crystal panel having a plurality of pixel cells in a lattice shape, and a projection optical system and projection screen for magnifying and projecting an original image formed on the liquid crystal panel, the image being compared with the original image. The image compression means for compressing the original image and forming the original image as the liquid crystal panel so that the absolute value of the difference between the length and the length becomes small so as to be different from the ratio of the length and width of the original image. And an image extension optical system for projecting the formed original image on the projection screen as a ratio between the length and the width of the original image. 8. The projection display device according to claim 7, wherein the image extension optical system is an optical lens provided on the projection screen side of the projection optical system. 8. The projection display device according to claim 7, wherein the image extension optical system is a convex mirror provided between the projection optical system and the projection screen. 10. The projection display according to claim 7, 8 or 9, wherein the pixel cells constituting the liquid crystal panel are compressed in the same direction by a compression ratio corresponding to the compression ratio in the compression direction of the original image. Device. Pixel cells for forming an original image in which the original image is compressed so as to be different from the ratio of the height and the width of the original image so that the absolute value of the difference between the length and the width of the image is smaller than the original image. A liquid crystal panel for a projection display device, characterized in that the shape is compressed in the same direction by a compression ratio corresponding to the compression ratio in the compression direction of the original image.